Competing phytoplankton undermines allelopathy of a bloom-forming dinoflagellate

Emily Katherine Prince, Tracey L. Myers, Jerome Naar, Julia Kubanek

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

Biotic interactions in the plankton can be both complex and dynamic. Competition among phytoplankton is often chemically mediated, but no studies have considered whether allelopathic compounds are modified by biotic interactions. Here, we show that compounds exuded during Karenia brevis blooms were allelopathic to the cosmopolitan diatom Skeletonema costatum, but that bloom allelopathy varied dramatically among collections and years. We investigated several possible causes of this variability and found that neither bloom density nor concentrations of water-borne brevetoxins correlated with allelopathic potency. However, when we directly tested whether the presence of competing phytoplankton influenced bloom allelopathy, we found that S. costatum reduced the growth-inhibiting effects of bloom exudates, suggesting that S. costatum has a mechanism for undermining K. brevis allelopathy. Additional laboratory experiments indicated that inducible changes to K. brevis allelopathy were restricted to two diatoms among five sensitive phytoplankton species, whereas five other species were constitutively resistant to K. brevis allelopathy. Our results suggest that competitors differ in their responses to phytoplankton allelopathy, with S. costatum exhibiting a previously undescribed method of resistance that may influence community structure and alter bloom dynamics.

Original languageEnglish (US)
Pages (from-to)2733-2741
Number of pages9
JournalProceedings of the Royal Society B: Biological Sciences
Volume275
Issue number1652
DOIs
Publication statusPublished - Dec 7 2008

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Keywords

  • Chemical ecology
  • Competition
  • Harmful algal bloom
  • Plankton
  • Variability

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)

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